Tuesday’s Red Sox-Astros matchups: Steven Wright vs. Jordan Lyles

After three major league relief appearances, the latter two of which were of the shutout variety and earned him wins, Steven Wright will get his first start in the big leagues Tuesday night at Minute Maid Park against right-hander Jordan Lyles and the Astros.

For Wright, a right-handed knuckleballer who came to Boston in the trade that sent former top prospect Lars Anderson to the Indians last July, getting the start will be nothing new. Indeed, in 19 games — all starts — with Triple-A Pawtucket this season, he owns a 3.89 ERA and 1.49 WHIP, numbers that looks considerably better given Wright’s hot July.

In 32 2/3 minor league innings, Wright owned a 2.20 ERA and 1.25 WHIP and threw a pair of complete-game shutouts. Mixed in that stretch were a pair of scoreless relief outings with the Red Sox when he went a combined 8 2/3 innings, allowing five hits and three walks while fanning five.

Count Farrell among those who have taken note of Wright’s improvements.

‘Compared to what he was in spring training or what he was in spring training from a delivery standpoint, just repeating his release point, it’s much more consistent strikes,’ Farrell said. ‘He’s starting to throw that knuckleball where he’s changing speeds on it, so to me in some ways he looks like a completely different pitcher from [his rough major league debut April 23], to what he’s been doing the last two outings. It’s a much-improved Steven Wright.

‘Early on, when he would get into jams ‘¦ he would just leap with his body. His body was out ahead of his arm too consistently. So when the inning would speed up on him, there was an inability or readiness to make those adjustments. He’s doing it now.’

Lyles (4-5), meanwhile, made his major league debut at age 20 in 2011 but has been generally unspectacular since then, and his 2013 campaign is no exception. He owns a 4.91 ERA — which would be his lowest total since arriving in the majors — and a 1.48 WHIP while fanning six batters per nine innings.

His last outing, a 6-3 loss to the Orioles on Thursday, was a pretty typical one: five runs (three earned) on nine hits and no walks in 5 2/3 innings. He found the strike zone with 62 percent of his pitches (58 of 94) and struck out five.

Lyles has not reached the 100-pitch mark in an outing since June 18, when he threw exactly 100 against the Brewers.

July 3, 2011, was the only other time Lyles pitched against the Sox. He limited Boston to one unearned run on three hits in five innings, but he did walk five. Jacoby Ellsbury and Dustin Pedroia finished a combined 3-for-7 with three walks in that contest.